1 <refentry id=
"vidioc-query-dv-preset">
3 <refentrytitle>ioctl VIDIOC_QUERY_DV_PRESET
</refentrytitle>
8 <refname>VIDIOC_QUERY_DV_PRESET
</refname>
9 <refpurpose>Sense the DV preset received by the current
16 <funcdef>int
<function>ioctl
</function></funcdef>
17 <paramdef>int
<parameter>fd
</parameter></paramdef>
18 <paramdef>int
<parameter>request
</parameter></paramdef>
19 <paramdef>struct v4l2_dv_preset *
<parameter>argp
</parameter></paramdef>
25 <title>Arguments
</title>
29 <term><parameter>fd
</parameter></term>
35 <term><parameter>request
</parameter></term>
37 <para>VIDIOC_QUERY_DV_PRESET
</para>
41 <term><parameter>argp
</parameter></term>
50 <title>Description
</title>
52 <para>The hardware may be able to detect the current DV preset
53 automatically, similar to sensing the video standard. To do so, applications
54 call
<constant> VIDIOC_QUERY_DV_PRESET
</constant> with a pointer to a
55 &v4l2-dv-preset; type. Once the hardware detects a preset, that preset is
56 returned in the preset field of &v4l2-dv-preset;. If the preset could not be
57 detected because there was no signal, or the signal was unreliable, or the
58 signal did not map to a supported preset, then the value V4L2_DV_INVALID is
66 <term><errorcode>EINVAL
</errorcode></term>
68 <para>This ioctl is not supported.
</para>
72 <term><errorcode>EBUSY
</errorcode></term>
74 <para>The device is busy and therefore can not sense the preset
</para>
84 sgml-parent-document: "v4l2.sgml"